Hi quick thinkers and slowpokes, it’s Julian for DNews.
Tim Welsh, a professor of Kinesiology at the University of Toronto recently wrote an article
asking, “what is the speed of thought?”
It’s a great question with a lot of different answers because thoughts can be huge complex
puzzles or simple reflexes.
They can originate internally or from external stimuli, and different people can have the
same thought at different speeds.
We thought we’d offer our own answer and to give us somewhere to start, let’s talk
about the basic unit of a thought.
A thought can be billions of neurons interacting with each other at once, swapping chemicals
between them to communicate.
So it could be said the most basic unit of thought is a neuron firing.
Neurons in your brain consist of cell bodies with dendrites branching from it, as well
as an axon that splits several times at the end.
People know that neurons send electrical impulses but it’s not like the electricity in your
house that works by passing freely moving electrons, so it’s not as instantaneous.
Instead neurons swap ions of different charges across the membrane of the axon.
By swapping them at the start of the axon by the cell body, it starts a chain reaction
down its length, like a row of people doing the wave.
When the signal gets to the end of the axon, the synaptic bundle will release neurotransmitters
across the synaptic cleft, which is the tiny space between the end of one neuron and the
beginning of the next.
The neurotransmitters float to the next neuron’s dendrites, and they tell the next neuron how
to fire.
So the total time it takes a cell to send an impulse down its axon and then diffuse
a neurotransmitter across the synapse is our most basic unit, and of course, this being
the brain we’re talking about, it gets even more complicated.
Because axons can either belong to gray matter or white matter.
40% of your brain’s volume is gray matter, it’s what you use for sensory perception,
speech, memory, emotions, and decision making.
It’s dense with cell bodies and the axons are short and don’t have a fatty protein
called myelin surrounding them.
White matter on the other hand doesn’t do the thought processing but is vital for connecting
different areas of gray matter because it has that myelin sheath.
That sheath is like the difference between a fiber optic cable and a 56k modem.
Without it, grey matter sends its electrical pulses at .5 to 10 meters per second.
With it, white matter’s action potential can travel up to 150 meters per second.
It needs that speed, because white matter axons in a man in his 20s can total over 176,000
kilometers.
The axons in white matter can be up to a meter long, which is good because that means fewer
synapses slowing the signal down.
A synapse is a gap between neurons of only 20 nanometers.
Some transmissions across the synapse can be quick; if the neurotransmitter opens up
the ion channels right away, the whole process can take just half a millisecond.
Most receptors however use the neurotransmitter to release another molecule and that secondary
messenger opens up the ion channels.
That can delay the signal anywhere from 30 milliseconds to a full second.
So between axon length, axon type, and neurotransmitter used, there’s a lot of variability in the
speed an individual neuron can send a message.
Now consider that a single neuron can have links with thousands of other neurons, meaning
your brain can have hundreds of trillions of synapses between its 86 billion neurons.
Plus there are different kinds of thought, like reflexes fast tracked to the spinal cord
or complex decisions that use billions of neurons across your brain.
All of these variables mean thoughts can be had and carried out at vastly different speeds.
It’s why some thoughts can be nearly instantaneous, like a sprinter starting to move only 150
milliseconds after a starter’s pistol; while others take much longer, like deciding whether
or not you should tell your crush how you feel.
It is possible to think faster though.
Reactions can become reflexes with practice, taking neurons and distance a signal has to
travel out of the equation to speed a thought up.
Or complex decisions can be made quicker with practice too.
Making different parts of your brain communicate by learning and considering new information
can improve the structural integrity of the white matter used, letting it send signals
faster, making you better at processing information.
It’s another great reason to keep coming back for more DNews.
I know, shameless plug.
You probably have about 86 billion neurons rolling around up there, and you may think
you only use 10% of them.
You don’t.
I hate that factoid and Anthony Carboni agrees.
Here’s the video with the truth.
What are your thoughts on thoughts?
Are you quick at learning and thinking or do you need more practice?
Let us know in the comments or facebook or twitter, subscribe for more brain food, and
I’ll see you next time on DNews.